A conventional distance measuring device is disclosed in U.S. Pat. No. 7,040,036 to Hui Chen Wang who is the wife of applicant and includes a wheel rotatably connected to a pole and a measuring unit is connected to a side of the wheel. The wheel includes a radius and rolls against a surface and the number of revolutions of the wheel can be counted by a counter so as to have the distance that the wheel travels. A handle is connected to the other end of the pole and includes a brake key and an initialization key, two respective cables are connected to the brake key and the initialization key so as to brake the wheel and initialize the counter. The pole is composed of sections which are foldably connected to each other and a positioning unit is located in the sections so as to control the relative positions of the sections of the pole.
However, the pole can only be folded to be two parallel sections at the mediate portion of the pole so that the folded status of the device still occupies a lot of space. The foldable pole cannot meet different requirements for users of different heights.
The present invention intends to provide a wheel distance measuring device which includes a retractable pole which can be collapsed to a short section and the length of the pole can be adjusted for different users' needs.